This invention relates generally to electromechanical resonant systems, and more particularly is directed to improvements in electromechanical systems of the type in which high frequency vibrations are generated in a transducer by means of a driving coil through which an alternating current is fed from a variable frequency oscillator.
Electromechanical resonant systems of the type described herein are suitable for use with ultrasonic dental handpieces wherein the work tool is coupled to the transducer for longitudinal vibration thereby via a connecting body which may also act as an acoustical impedance transformer. As is known in the art, maximum vibration amplitude is obtained when the vibration frequency is at the resonant frequency of the transducer, tool holder and work tool. The resonant frequency is typically such that the overall length of the vibrating structure is an integral number of half-wavelengths of the longitudinal vibrations, although, as set forth in my co-pending U.S. Patent Application, Ser. No. 692,291 filed June 3, 1976, the relationship between the length of the foregoing assembly and the frequency of vibration need not be in terms of half-wavelengths.
In order to obtain the optimum amplitude of vibration, the frequency of the electrical oscillations within the transducer driving coil must be correlated to the natural frequency of vibration of the mechanical portion of the system.